336 research outputs found
Movements and Area Use of Belugas, Delphinapterus leucas, in a Subarctic Alaskan Estuary
Seasonal movements of 14 belugas in Cook Inlet, Alaska, were monitored by satellite telemetry between July and March in 2000â03. Whales used waters in the upper Cook Inlet intensively between summer and late autumn and dispersed to mid-inlet offshore waters during winter months. All whales remained in Cook Inlet the entire time they were tracked, and several whales were tracked through March. During summer and early fall, movements were clearly concentrated in specific areas, generally river mouths or bays, where whales were likely feeding on fish runs. Average daily travel distances ranged from 11 to 30 km per day. Monthly home ranges, estimated using the 95% kernel probability distribution of average daily positions, were smallest in August (982 km2), increased throughout autumn, and peaked in winter (reaching approximately 5000 km2). The seasonal variation in distribution and movement patterns displayed by belugas in Cook Inlet affect the sighting rates and seasonal abundance estimates obtained for this depleted population.Les dĂ©placements saisonniers de 14 bĂ©lugas du dĂ©troit de Cook, en Alaska, ont fait lâobjet dâune surveillance au moyen dâun Ă©metteur par satellite entre les mois de juillet et mars 2000 Ă 2003. Cela a permis de remarquer que les baleines se tenaient beaucoup dans les eaux de la partie supĂ©rieure du dĂ©troit de Cook de lâĂ©tĂ© jusquâĂ la fin de lâautomne, mais quâelles se dispersaient dans les eaux du large du milieu du dĂ©troit pendant les mois dâhiver. Toutes les baleines sont restĂ©es dans le dĂ©troit de Cook pendant toute la durĂ©e de surveillance, et plusieurs baleines ont Ă©tĂ© suivies jusquâau mois de mars. LâĂ©tĂ© et au dĂ©but de lâautomne, les dĂ©placements Ă©taient nettement concentrĂ©s dans des endroits spĂ©cifiques, gĂ©nĂ©ralement dans les embouchures ou les baies, oĂč les baleines se nourrissaient probablement de poissons. En moyenne, les baleines se dĂ©plaçaient sur des distances variant de 11 Ă 30 km par jour. Câest en aoĂ»t que le domaine vital mensuel, estimĂ© par la mĂ©thode du noyau en fonction dâune densitĂ© de probabilitĂ© de 95 % des positions quotidiennes moyennes, Ă©tait le plus petit (982 km2), aprĂšs quoi il augmentait Ă lâautomne et culminait lâhiver (oĂč il atteignait environ 5 000 km2). La variation saisonniĂšre caractĂ©risant la rĂ©partition et les dĂ©placements des bĂ©lugas dans le dĂ©troit de Cook exerce une influence sur le taux dâobservations et sur les estimations dâabondance saisonniĂšre obtenues pour cette population en dĂ©clin
Baffin Bay Narwhal Population Distribution and Numbers: Aerial Surveys in the Canadian High Arctic, 2002â04
Aerial surveys of narwhals (Monodon monoceros) were conducted in the Canadian High Arctic during the month of August from 2002 to 2004. The surveys covered the waters of Barrow Strait, Prince Regent Inlet, the Gulf of Boothia, Admiralty Inlet, Eclipse Sound, and the eastern coast of Baffin Island, using systematic sampling methods. Fiords were flown along a single transect down the middle. Near-surface population estimates increased by 1.9 %â 8.7% when corrected for perception bias. The estimates were further increased by a factor of approximately 3, to account for individuals not seen because they were diving when the survey plane flew over (availability bias). These corrections resulted in estimates of 27 656 (SE = 14 939) for the Prince Regent and Gulf of Boothia area, 20 225 (SE = 7285) for the Eclipse Sound area, and 10 073 (SE = 3123) for the East Baffin Island fiord area. The estimate for the Admiralty Inlet area was 5362 (SE = 2681) but is thought to be biased. Surveys could not be done in other known areas of occupation, such as the waters of the Cumberland Peninsula of East Baffin, and channels farther west of the areas surveyed (Peel Sound, Viscount Melville Sound, Smith Sound and Jones Sound, and other channels of the Canadian Arctic archipelago). Despite these probable biases and the incomplete coverage, results of these surveys show that the summering range of narwhals in the Canadian High Arctic is vast. If narwhals are philopatri to their summering areas, as they appear to be, the total population of that range could number more than 60 000 animals. The largest numbers are in the western portion of their summer range, around Somerset Island, and also in the Eclipse Sound area. However, these survey estimates have large variances due to narwhal aggregation in some parts of the surveyed areas.Des levĂ©s aĂ©riens ont Ă©tĂ© effectuĂ©s dans lâExtrĂȘme arctique canadien dans le but de rĂ©pertorier les populations de narvals (Monodon monoceros) et ce, du mois dâaoĂ»t 2002 Ă aoĂ»t 2004. Les levĂ©s, rĂ©alisĂ©s Ă lâaide de mĂ©thodes dâĂ©chantillonnage systĂ©miques, visaient les eaux du dĂ©troit de Barrow, de lâinlet Prince-RĂ©gent, du golfe de Boothia, de lâinlet de lâAmirautĂ©, du dĂ©troit dâĂclipse et de la cĂŽte est de lâĂźle de Baffin. Les fiords ont Ă©tĂ© survolĂ©s le long dâun simple transect situĂ© dans le milieu. Les estimations de population prĂšs de la surface augmentaient de 1,9 % Ă 8,7 % une fois redressĂ©es pour tenir compte du biais de perception. Par ailleurs, les estimations ont Ă©tĂ© de nouveau rĂ©visĂ©es Ă la hausse moyennant un facteur dâenviron 3 afin de tenir compte des individus qui nâont pas Ă©tĂ© vus parce quâils se mettaient Ă plonger en prĂ©sence de lâavion effectuant les levĂ©s (biais de disponibilitĂ©). Ces redressements ont donnĂ© lieu Ă des estimations de 27 656 (SE = 14 939) pour la rĂ©gion de lâinlet Prince-RĂ©gent et du golfe de Boothia, de 20 225 (SE = 7 285) pour la rĂ©gion du dĂ©troit dâĂclipse et de 10 073 (SE = 3 123) pour la rĂ©gion du fiord de lâest de lâĂźle de Baffin. Quand Ă lâinlet de lâAmirautĂ©, lâestimation sâest chiffrĂ©e Ă 5 362 (SE = 2 681), mais lâon croit que cette estimation pourrait ĂȘtre biaisĂ©e. Des levĂ©s nâont pas pu ĂȘtre effectuĂ©s dans dâautres zones dâoccupation connues, comme dans les eaux de la pĂ©ninsule Cumberland dans lâest de Baffin de mĂȘme que dans les chenaux plus Ă lâouest des rĂ©gions examinĂ©es (dĂ©troit de Peel, dĂ©troit du Vicomte de Melville, dĂ©troit de Smith, dĂ©troit de Jones et dâautres chenaux de lâarchipel Arctique canadien). MalgrĂ© la possibilitĂ© que les donnĂ©es soient biaisĂ©es et que certaines zones nâaient pas Ă©tĂ© examinĂ©es, les rĂ©sultats de ces levĂ©s montrent que la rĂ©partition dâĂ©tĂ© des narvals dans lâExtrĂȘme arctique canadien est vaste. Si les narvals sont philopatriques Ă leurs aires dâĂ©tĂ©, comme il semblerait ĂȘtre le cas, la population totale de ce parcours pourrait dĂ©passer les 60 000 individus. Les plus grands nombres se trouvent dans la partie ouest de cette rĂ©partition, soit prĂšs de lâĂźle Somerset et dans la rĂ©gion du dĂ©troit dâĂclipse. Cependant, les estimations dĂ©coulant de ces levĂ©s ont de grandes variances en raison du regroupement des narvals dans certaines parties des rĂ©gions visĂ©es par les levĂ©s
From Greenland to Canada in Ten Days: Tracks of Bowhead Whales, Balaena mysticetus, across Baffin Bay
Five bowhead whales (Balaena mysticetus) were instrumented with satellite transmitters in northwestern Disko Bay, West Greenland, in May 2001. Best results were obtained when tags were deployed with a pole rather than a pneumatic gun. At least three of the tagged whales remained in the northwestern part of the bay for one to two weeks after tagging. A male and a female whale moved from Disko Bay to northern Canada. They left Disko Bay 11 days apart and took different routes across Baffin Bay to the southern part of the North Water polynya, just east of the entrance to Lancaster Sound. The whales crossed the central part of Baffin Bay relatively rapidly (travel time of 9-10 days, 3.1 and 4.5 km/h). Dive behaviour of one whale was monitored and showed changes in dive depths, dive rates, and surfacing times in different localities, indicating behavioural changes probably related to feeding. The whales were presumably feeding in both Disko Bay in May and in the southern part of the North Water (southeast of Bylot Island) in June. This study confirms whalers' observations that bowhead whales move between West Greenland and the east coast of Baffin Island.En mai 2001, cinq baleines boréales (Balaena mysticetus) ont été équipées d'émetteurs spatiaux dans le nord-ouest de la baie de Disko (Groenland occidental). Les meilleurs résultats ont été obtenus lorsque les marqueurs ont été apposés avec une perche plutÎt qu'avec un fusil à air comprimé. Au moins trois des baleines marquées sont restées dans la partie nord-ouest de la baie pendant une à deux semaines aprÚs le marquage. Deux individus, un mùle et une femelle, se sont déplacés de la baie de Disko au nord du Canada. Ils ont quitté la baie à 11 jours d'écart et ont emprunté des trajets différents pour traverser la baie de Baffin et rejoindre la partie méridionale de la polynie de l'Eau du Nord, située juste à l'est de l'entrée du détroit de Lancaster. Les baleines ont traversé la partie centrale de la baie de Baffin assez vite (en 9 et 10 jours, soit 3,1 et 4,5 km/h). On a suivi le comportement de plongée d'une baleine, qui a montré des changements dans la profondeur des plongées, leur fréquence et le temps en surface à divers endroits, révélant des modifications du comportement probablement associées au nourrissage. On suppose que les baleines s'alimentaient dans la baie de Disko en mai aussi bien que dans la partie méridionale de l'Eau du Nord (au sud-est de l'ßle Bylot) en juin. Cette étude confirme les observations des baleiniers à l'effet que les baleines boréales se déplacent entre l'ouest du Groenland et la cÎte est de l'ßle de Baffin
Mineral resource information in support of national, regional and local planning : Devon (comprising Devon, Plymouth, Torbay, Dartmoor National Park and part of Exmoor National Park)
This report is one of a series prepared by the British Geological Survey for various administrative areas in England for the Office of the Deputy Prime Ministerâs research project Mineral Resource Information in Support of National, Regional and Local Planning.
The accompanying maps relate to the county of Devon and delineates the mineral resources of current, or potential, economic interest in the area and the sites where minerals are or have been worked. It also relates these to national planning designations, which may represent constraints on the extraction of minerals.
Three major elements of information are presented:
âą the geological distribution and importance of mineral resources;
âą the extent of mineral planning permissions and the location of current mineral workings; and
âą the extent of selected, nationally-designated planning constraints.
This wide range of information, much of which is scattered and not always available in a consistent and convenient form, is presented on two digitally-generated summary map on the scale of 1:100 000. This scale is convenient for the overall display of the data and allows for a legible topographic base on which to depict the information. However, all the data are held digitally at larger scales using a Geographical Information System (GIS), which allows easy revision, updating and customisation of the information together with its possible integration with other datasets. The information will form part of a Summary of the Mineral Resources of the South West Region.
The purpose of the work is to assist all interested parties involved in the preparation and review of development plans, both in relation to the extraction of minerals and the protection of mineral resources from sterilisation. It provides a knowledge base, in a consistent format, on the nature and extent of mineral resources and the environmental constraints, which may affect their extraction. An important objective is to provide baseline data for the long term. The results may also provide a starting point for discussion on specific planning proposals for minerals extraction or on proposals, which may sterilise resources.
It is anticipated that the map and report will also provide valuable background data for a much wider audience, including the different sectors of the minerals industry, other agencies and authorities (e.g. The Planning Inspectorate Agency, the Environment Agency, The Countryside Agency and English Nature), environmental interests and the general public.
Basic mineral resource information is essential to support mineral exploration and development activities, for resource management and land-use planning, and to establish baseline data for environmental impact studies and environmental guidelines. It also enables a more sustainable pattern and standard of development to be achieved by valuing mineral resources as national assets.
The mineral resources covered are sand and gravel, crushed rock aggregate, brick clay, kaolin, ball clay, building stones, hydrocarbons and metalliferous mineralisation
The algebra of lexical semantics
Abstract. The current generative theory of the lexicon relies primar-ily on tools from formal language theory and mathematical logic. Here we describe how a different formal apparatus, taken from algebra and automata theory, resolves many of the known problems with the gener-ative lexicon. We develop a finite state theory of word meaning based on machines in the sense of Eilenberg [11], a formalism capable of de-scribing discrepancies between syntactic type (lexical category) and se-mantic type (number of arguments). This mechanism is compared both to the standard linguistic approaches and to the formalisms developed in AI/KR. 1 Problem Statement In developing a formal theory of lexicography our starting point will be the informal practice of lexicography, rather than the more immediately related for-mal theories of Artificial Intelligence (AI) and Knowledge Representation (KR). Lexicography is a relatively mature field, with centuries of work experience an
Magnetic Field Generation in Stars
Enormous progress has been made on observing stellar magnetism in stars from
the main sequence through to compact objects. Recent data have thrown into
sharper relief the vexed question of the origin of stellar magnetic fields,
which remains one of the main unanswered questions in astrophysics. In this
chapter we review recent work in this area of research. In particular, we look
at the fossil field hypothesis which links magnetism in compact stars to
magnetism in main sequence and pre-main sequence stars and we consider why its
feasibility has now been questioned particularly in the context of highly
magnetic white dwarfs. We also review the fossil versus dynamo debate in the
context of neutron stars and the roles played by key physical processes such as
buoyancy, helicity, and superfluid turbulence,in the generation and stability
of neutron star fields.
Independent information on the internal magnetic field of neutron stars will
come from future gravitational wave detections. Thus we maybe at the dawn of a
new era of exciting discoveries in compact star magnetism driven by the opening
of a new, non-electromagnetic observational window.
We also review recent advances in the theory and computation of
magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo
theory. These advances offer insight into the action of stellar dynamos as well
as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field
generation in stars to appear in Space Science Reviews, Springe
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS
The chi_b(nP) quarkonium states are produced in proton-proton collisions at
the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS
detector. Using a data sample corresponding to an integrated luminosity of 4.4
fb^-1, these states are reconstructed through their radiative decays to
Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks
corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new
structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is
also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes.
This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table,
corrected author list, matches final version in Physical Review Letter
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